U.S. patent number 3,679,841 [Application Number 05/033,366] was granted by the patent office on 1972-07-25 for magnetic tape head skew adjustment.
This patent grant is currently assigned to Storage Technology Corporation. Invention is credited to Zoltan L. Herger, Dennis R. Olmsted.
United States Patent |
3,679,841 |
Herger , et al. |
July 25, 1972 |
MAGNETIC TAPE HEAD SKEW ADJUSTMENT
Abstract
Skew adjusting apparatus for a magnetic tape unit includes a
right angle mounting plate for the magnetic head with one surface
being curved with a radius of curvature having a center line
coincidental with the center line of the tape path. The curved
surface is biased toward two guiding pins. The mounting plate moves
with the curved surface riding on the pins so that the magnetic
head is rotated about the center line of the tape path.
Inventors: |
Herger; Zoltan L. (Northglenn,
CO), Olmsted; Dennis R. (Westminster, CO) |
Assignee: |
Storage Technology Corporation
(Boulder, CO)
|
Family
ID: |
21870009 |
Appl.
No.: |
05/033,366 |
Filed: |
April 30, 1970 |
Current U.S.
Class: |
360/291.2;
G9B/5.201 |
Current CPC
Class: |
G11B
5/56 (20130101) |
Current International
Class: |
G11B
5/56 (20060101); G11b 005/56 () |
Field of
Search: |
;179/1.2CA,1.2K
;274/4A,11A |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Konick; Bernard
Assistant Examiner: Lucas; Jay P.
Claims
What is claimed is:
1. Skew adjusting apparatus for a magnetic tape unit in which a
magnetic tape is driven along a tape path comprising:
a magnetic tape head,
a mounting plate, said magnetic head being mounted on one surface
of said mounting plate, another surface of said plate being curved
with a radius of curvature having a center line coincidental with
the center line of said tape path, said mounting plate having a
notch in the other surface thereof,
guide means mounted on said magnetic tape unit for guiding the
curved surface of said plate in movement which rotates said
magnetic tape head about a point which lies in the center line of
said tape path,
a vernier screw threadably mounted on said magnetic tape unit, said
mounting plate having a surface which is angled to bear against an
end of said vernier screw, rotation of said vernier screw causing
movement of said mounting plate so that said head rotates about
said center line of said tape path, and
a spring having one end disposed in said notch for biasing said
mounting plate toward said vernier screw.
Description
BACKGROUND OF THE INVENTION
This invention relates to a skew adjustment for a magnetic tape
unit and more particularly to apparatus for mounting the magnetic
read-write head to provide rotation of the magnetic head about a
point in the center line of the tape path.
In magnetic tape recording and reproducing systems the skew of the
magnetic head must be adjusted to average out head read-write
center line imperfections. In the past, magnetic heads have been
adjusted by rotating them about a point at the edge of the head, or
even further from the center of the tape path. When the magnetic
head is pivoted about such a point, the center of the magnetic head
is displaced from the center line of the tape path. The tape path
over the head is altered.
SUMMARY OF THE INVENTION
In accordance with an important aspect of this invention the tape
head skew adjusting mount rotates the head about a point on the
center line of the tape path. Because of this, the tape path over
the head is not altered by skew adjustment.
One of the advantages of this invention is that the skew adjustment
means maintains the coincidence between the center line of the
magnetic head and the center line of the magnetic tape at all
times.
In accordance with another aspect of this invention the skew
adjustment vernier and the locking screw are separated. Because of
this the skew adjustment can be locked while the adjustment is
maintained with the vernier screw. In prior art adjustments, a
locking system incorporated on the adjusting screw is used. In such
systems the previously obtained skew settings can be altered during
the locking operations.
Another advantage of this invention is that the magnetic tape head
mount is very stable and capable of adjustment to precisely the
desired position.
DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a plan view of the skew adjustment apparatus; and
FIG. 2 shows a side view of the skew adjustment apparatus.
DESCRIPTION OF A PARTICULAR EMBODIMENT
The figures show a portion of a magnetic tape unit including a
magnetic head 10 and a magnetic tape 11 which is driven along the
tape path. The tape path is fixed with respect to the reference
datum 12.
The magnetic head 10 is mounted on a right angle plate 13. The
magnetic head is mounted on one angle of the right angle plate
while the other angle rides in a slot in the main head mount. The
other angle has a curved surface. The curved surface has a radius
of curvature with a center line which is coincidental with the
center line of the tape path. As shown in FIG. 1, the center of the
radius of curvature is also in the center of the head 10.
The curved surface of the right angle plate rides against dowel
pins 14 and 15 mounted in the main head mount. These dowel pins
provide means for guiding the curved surface of the plate 13 in
movement which rotates the magnetic tape head 10 about a point
which lies in the center line of the tape path.
The right angle plate 13 is biased toward the pins 14 and 15 by a
leaf spring 16 which is mounted on the plate 13 and which works
against the opposite sides of the pins 14 and 15.
A vernier screw 18 is threadably mounted in a block which in turn
is mounted to the main head mount. The side of the other angle of
the right angle plate has a protrusion 17 angled away from the
side. This angled surface 17 bears against the end of vernier
adjustment screw 18.
The right angle plate 13 is biased toward the vernier adjustment
screw 18 by a leaf spring 21 which is mounted on the main head
block. One end of the leaf spring 21 is disposed in a notch in the
curved surface of the mounting plate to bias the mounting plate
toward the vernier screw.
Spring plungers, including the spring plunger 19, load the right
angle plate 13 against the registering surface on the main head
mount. A locking screw 20 extends through the main head mount and
locks the right angle plate in a position to which it has been set
by adjustment of the vernier screw 18.
A skew adjustment is made in the following manner. The locking
screw 20 is loosened. With the locking screw 20 loosened, the
spring forces now control head stability. Spring plunger 19 loads
the angle plate 13 against the registering surface on the head
mount; spring 16 loads the plate against the dowel pins 14 and 15;
and spring 21 loads the angle plate against the vernier screw 18.
This eliminates head oscillations during the adjustment procedure.
The vernier adjustment screw 18 is rotated to obtain the proper
head alignment. Then the locking screw 20 is tightened to maintain
the settings.
During skew adjustment the head 10 is pivoted about a point in the
center line of the tape path. This is as contrasted to other skew
adjustment devices which pivot or gyrate the head about a center
which is outside the tape center line. The advantage of this
invention is that coincidence between tape center line and head
center line is maintained at all times. The tape path over the head
is not altered by skew adjustment.
Another advantage is that the adjustment vernier 18 is separated
from the locking screw 20. Because of this the adjustment made with
the vernier screw 18 can be maintained while it is being locked
with the locking screw 20.
While a particular embodiment of the invention has been shown and
described modifications are within the true spirit and scope of the
invention. The appended claims are intended to cover such
modifications.
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